.kb1-container {
  height: 100vh;
  flex-direction: column;
}

/* 顶部渐变区域 */
.top-gradient {
  background: linear-gradient(135deg, #D4E9FC 0%, #B9DEF7 100%);
  padding: 24px 24px 24px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
}

.icon-circle {
  width: 40px;
  height: 40px;
  background-color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.page-title {
  font-size: clamp(1.5rem, 5vw, 2.2rem);
  font-weight: bold;
  color: #1EB7D8;
  margin: 0;
}

.page-tip {
  background-color: rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  padding: 16px;
  display: inline-block;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.page-tip p {
  color: #333;
  font-size: clamp(1rem, 3vw, 1.25rem);
  font-weight: 500;
  margin: 0;
}

/* 主要内容区 */
.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px 80px;
  margin-top: 15px;
  //margin-top: -16px;
}

.textbook-card {
  border-radius: 24px;
  margin-bottom: 20px;
  text-align: center;
  position:relative;
  background-color: #ffffff;
  box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1);
  //0 4px 6px -4px rgb(0 0 0 / 0.1)
}

.textbook-title {
  font-size: 1.25rem;
  font-weight: bold;
  color: #333;
  height: 40px;
  line-height: 40px;
}

.unit-list-title {
  margin-bottom: 15px;
  text-align: center;
}

.unit-list-title h3 {
  font-size: 1.25rem;
  font-weight: bold;
  color: #333;
  margin: 0;
}

.unit-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.unit-card {
  border-radius: 16px;
  transition: all 0.3s ease;
  transform: translateY(10px);
  position: relative;
}

.unit-card.card-visible {
  opacity: 1;
  transform: translateY(0);
}

.unit-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.unit-card.last-studied {
  border: 2px solid rgba(255, 82, 82, 0.3);
}
.unit-card-last-studied {
  border-radius: 16px;
  transition: all 0.3s ease;
  transform: translateY(10px);
  position: relative;
  border: 2px solid rgba(255, 82, 82, 0.3);
}

.last-study-badge {
  position: absolute;
  top: -12px;
  left: 16px;
  background-color: #FF5252;
  color: white;
  font-size: 12px;
  font-weight: bold;
  padding: 4px 12px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  gap: 4px;
}

.unit-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.unit-title {
  font-size: 1.125rem;
  font-weight: bold;
  color: #333;
  margin: 0;
}

.completionStatus-tag {
  border-radius: 12px;
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 12px;
}

.study-buttons {
  display: flex;
  gap: 12px;
}

.study-buttons button {
  flex: 1;
  border-radius: 12px;
  padding: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s ease;
}

.study-buttons button:hover:not(:disabled) {
  transform: scale(1.05);
}

.study-buttons button:disabled {
  opacity: 0.5;
}

.vocab-btn {
  background-color: rgba(255, 158, 125, 0.1);
  color: #FF9E7D;
  border: none;
}

.article-btn {
  background-color: rgba(140, 215, 144, 0.1);
  color: #8CD790;
  border: none;
}

.encouragement {
  margin-top: 32px;
  background-color: rgba(212, 233, 252, 0.5);
  border-radius: 16px;
  padding: 16px;
  text-align: center;
}

.encouragement p {
  color: #1EB7D8;
  font-weight: 500;
  margin: 0;
}

/* 底部导航 */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: white;
  box-shadow: 0 -2px 15px rgba(0, 0, 0, 0.05);
  padding: 16px 24px;
}

.nav-grid {
  --gap: 0;
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  color: #999;
}

.nav-item.active {
  color: #1EB7D8;
}

.nav-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 4px;
}

.nav-item.active .nav-icon {
  background-color: #D4E9FC;
}

.nav-item span {
  font-size: 12px;
}

/* 响应式调整 */
@media (max-width: 768px) {
  .top-gradient {
    padding: 16px;
  }
  
  .main-content {
    padding: 0 16px 80px;
  }
  
  .study-buttons {
    //flex-direction: column;
  }
}